The present invention relates to an electrochromic display drive system and, more particularly, to an electrochromic display drive system in an electronic timepiece.
The electrochromic display device inherently possesses a memory effect, wherein the coloration state or the bleached state is maintained for a considerably long period of time after removal of application of the driving signal. Recently, an electronic timepiece has been developed, which employs a digital display device comprising an electrochromic display cell.
In a battery powered electronic timepiece, the information display is held by the electrochromic display cell even when a battery is removed from the electronic timepiece to be exchanged with a new one. Under these conditions, when a new battery is disposed in the electronic timepiece, there is a possibility that the drive logic signal derived from a driver circuit is not correlated with the actual display state of the electrochromic display cell.
More specifically, there is a possibility that a coloration voltage signal is applied to a segment electrode which has been held in the coloration state. This will deteriorate the electrochromic display cell due to the over charge applied to a specific display segment. Moreover, the inconsistency between the drive logic signal and the actual display state precludes an accurate information display and a clean information display.
Accordingly, an object of the present invention is to provide a novel electrochromic display drive system for ensuring an accurate information display.
Another object of the present invention is to provide an electrochromic display drive system suited for a battery powered electronic timepiece.
Still another object of the present invention is to provide a control system for stabilizing an initial condition of an electrochromic display device when a power supply switch is turned on.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a detection means is provided in an electronic timepiece for developing a detection output when a new supply of power is initiated. A driver circuit is constructed so as to bleach all of the segments in the electrochromic display device when the detection output is developed from the detection means.
In a preferred form, the detection output is applied to a drive logic circuit in order to place the drive logic circuit in a standby condition pending the subsequent coloration operation.